Cromoglycate induces a rebound effect on blood/milk permeability in subclinical mastitis

Chronic subclinical mastitis represents a vicious cycle of constant tissue irritation by bacteria and inflammatory response of the host. Antibiotics have proven relatively inefficient in eliminating chronic mastitic infections. The use of anti-inflammatory agents in mastitis is controversial. Theoretically, the inflammation should not be suppressed as this is a host defence mechanism of the body. However, because it is uncertain whether the infection or chronic inflammation causes more harm to the tissue, there have been efforts to use anti-inflammatory agents such as glucocorticoids and antipyretic analgetics. The problem is that there is insufficient evidence as to which inflammatory mediators (histamine, kinins, prostaglandins, leukotrienes, PAF, interleukin-1 etc.) alone or in combination are important in mastitis.     

Interaction of sub-epithelial connective tissue components with Staphylococcus aureus and coagulase-negative staphylococci from bovine mastitis

Staphylococcus aureus and coagulase-negative staphylococci (CNS) isolated from bovine mastitis were examined for their ability to interact with 125I-labelled fibronectin, fibrinogen and type II collagen. Their relative surface hydrophobicity and production of extracellular capsule were also investigated. Almost all S. aureus strains bound fibronectin (mean value 23%), fibrinogen (mean value 12%) and type II collagen (mean value 16%). CNS bound fibronectin (mean value 6%) and type II collagen (mean value 7%), but not fibrinogen (mean value 2%). The specificity of binding of these proteins to S. aureus strain F1440 and to coagulase-negative Staphylococcus chromogenes strain BO52 was studied by adding an excess of unlabelled proteins. Fibronectin and collagen binding were observed to be specific, varying between 50 and 75%, whereas the specificity of fibrinogen binding to S. aureus strain F1440 was lower (26%). Most of the S. aureus strains (63%) showed very high surface hydrophobicity (autoaggregation) or lower hydrophobicity (29% of the strains) and the rest were hydrophilic. None of the CNS strains autoaggregated, 44% were classified as hydrophilic strains. Hydrophilic strains (except the reference strains) did not show extracellular capsule production. However, the encapsulated (reference) strains showed low binding to these proteins as compared to their unencapsulated variants. Pre-treatment of S. aureus strain F1440 and S. chromogenes strain BO52 with trypsin decreased their fibronectin binding capacity and surface hydrophobicity, whereas pre-treatment with bovine milk (except on collagen binding to strain F1440) did not significantly affect binding to these proteins. These data indicate that S. aureus and CNS isolated from bovine udder infection have the ability to bind to tissue matrix and plasma proteins which may be exposed in the traumatized or toxin-damaged udder epithelial lesions.     

Fimbria-like adhesive factor (EAF 44) from verocytotoxigenic Escherichia coli of bovine origin

An adhesin with fimbria-like properties was present in four strains of verocytotoxigenic Escherichia coli isolated from diarrhoeic calves in Brazil.     

The response of phospholipase C/protein kinase C and adenylyl cyclase/protein kinase A pathways in porcine theca interna cells to opioid agonist FK 33-824

Opioids were found as factors affecting porcine ovarian steroidogenesis. The mechanism of opioid action, however, on porcine theca interna cells is completely unknown. Therefore, the present study was designed to investigate the possible involvement of two intracellular pathways, phospholipase C/protein kinase C and adenylyl cyclase/protein kinase A, in opioid signal transduction in porcine theca cells treated with mu opioid receptor agonist, FK 33-824. Incubation of the cells for 4 h with FK 33-824 at the dose 1 nM resulted in decreases in inositol phosphate accumulation as well as androstenedione (A(4)), testosterone (T), and estradiol (E(2)) secretions. Protein kinase C (PKC) inhibitors, staurosporine (1-100 nM), D-sphingosine (10-500 nM), and PKCi (100-2000 nM), both added alone and together with the opioid agonist, depressed release of the steroid hormones. PKC activator, phorbol ester (PMA, 1-100 nM), used alone was without effect on theca cell steroidogenesis, but added in combination with FK 33-824 abolished inhibitory influence of the opioid on A(4), T, and E(2) output. The steroid hormone secretion by PKC-deficient theca cells was inhibited by the opioid agonist. FK 33-824 also suppressed PKC activity reducing [(3)H]PDBu specific binding to theca cells, whereas ionomycin (a positive control) increased labeled phorbol ester binding to the cells. In the next experiment, cAMP release from theca cells during 2 and 4 h incubations with FK 33-824 (1-100 nM), naloxone (10 microM; opioid receptor antagonist), and LH (100 ng/mL; a positive control) was examined. FK 33-824 at the dose 1 nM inhibited cAMP secretion during 2 h incubation, but had no effect during longer incubation. LH in a manner independent on incubation time multiplied cAMP release. Protein kinase A inhibitor, PKAi (100-2000 nM), alone and in combination with FK 33-824 (1 nM), inhibited A(4), T, and E(2) secretions by theca cells. PKA activator, 8BrcAMP (10-1000 microM), stimulated the steroid hormone release, but this stimulatory effect was diminished in the presence of FK 33-824. The results allow to suggest that opioid peptides affect porcine theca cell steroidogenesis and their acute action on the cells is connected with the inhibition of phospholipase C/protein kinase C and adenylyl cyclase/protein kinase A signal transduction systems.     

Characteristics of calves produced with sperm sexed by flow cytometry/cell sorting

The objectives of this study were to determine whether calves produced by sexed sperm differed from controls and to what extent the sex ratio of calves was altered by the sexing procedure. Data were collected from 1,169 calves produced from sperm sexed by flow cytometry/cell sorting after staining with Hoechst 33342, and 793 calves produced from control sperm during breeding trials between 1997 and 2001. Least squares ANOVA were completed using factors of treatment (sexed vs. control sperm), 19 management groups from 13 field trials, and calf sex. Responses analyzed include gestation length, birth weight, calving ease, calf vigor, weaning weight, abortion rate, and death rates (neonatal and through weaning). No significant difference was observed for any response due to treatment or treatment interactions (P > 0.10). Therefore, calves produced from sexed sperm grew and developed normally both pre- and postnatally. A neurological disorder was observed in four control calves and one sexed calf from one farm. No gross anatomical abnormalities were reported for any calves in the study. Differences were observed for all responses among management groups (P < 0.03 for abortions and P < 0.01 for all other responses). Heifer and bull calves differed (P < 0.001) in gestation length (278.4 and 279.6 d), birth weight (32.8 and 35.2 kg), calving ease (1.15 and 1.30), and weaning weight (233 and 247 kg). Gestation length did not affect characteristics of calves. The sex ratio at birth of calves from unsexed control sperm was 49.2% male. Sexing accuracy of X-sorted sperm was 87.8% female calves, and Y-sorted sperm produced 92.1% male calves. Flow cytometry/cell sorting can be used to preselect sex of calves safely with approximately 90% accuracy.     

A biomechanical comparison of headless tapered variable pitch compression and ao cortical bone screws for fixation of a simulated midbody transverse fracture of the proximal sesamoid bone in horses

OBJECTIVE: To compare mechanical properties and failure characteristics of 2 methods of fixation for repair of a transverse, midbody fracture of the proximal sesamoid bone (PSB): 4.5-mm AO cortical bone screw (AO) placed in lag fashion and 4/5-mm Acutrak (AT) self-compressing screw. STUDY DESIGN: An in vitro biomechanical evaluation of intact forelimb preparations and forelimb preparations with a simulated midbody PSB fracture stabilized by a bone screw. SAMPLE POPULATION: Sixteen paired and 8 unilateral cadaveric equine forelimbs. METHODS: A midbody transverse osteotomy was created in the medial PSB of bilateral forelimbs of 8 equine cadavers. The osteotomized PSB in 1 forelimb from each cadaver was repaired with an AO screw. The osteotomized PSB in each contralateral limb was repaired with an AT screw. Eight unilateral intact control limbs were also studied. Mechanical properties were determined from axial compression, single cycle to failure, load-deformation curves. Failure characteristics were determined by evaluation of video images and radiographs. RESULTS: No statistically significant differences were found between repair groups. Both AO and AT groups had significantly lower mechanical properties than intact limbs except for stiffness. CONCLUSION: AO and AT constructs were mechanically comparable when used to stabilize a simulated midbody fracture of the medial PSB. Both constructs were mechanically inferior to intact limbs. Clinical Relevance- The AT screw should be considered for clinical use because of the potential for less soft tissue impingement and superior biocompatibility compared with the stainless-steel AO screw. However, postoperative external coaptation is necessary to augment initial fracture stability for either fixation method, and to maintain a standing metacarpophalangeal joint dorsiflexion angle between 150 degrees and 155 degrees.     

Treatment of a well differentiated pulmonary adenocarcinoma in a cat by pneumonectomy and adjuvant mitoxantrone chemotherapy

Primary lung neoplasia is a rare condition of older cats. This report describes a case of left-sided pulmonary collapse, secondary to pulmonary adenocarcinoma in an 11-year-old cat. Left sided pneumonectomy was performed, and adjuvant chemotherapy with mitoxantrone (Novantrone; Lederle) was administered every 3 to 5 weeks, for 10 doses after surgery. Thirty-four months after surgery, the cat remains well and has no radiographic evidence of pulmonary metastasis.     

A malar granular cell tumor in a djungarian hamster

'Granular cell' tumor observed in the malar subcutis of a Djungarian hamster was examined to determine its cellular origin. Histologically, the tumor consisted of a solid growth of oval or spindle-shaped large cells with abundant cytoplasm filled with eosinophilic granules that were periodic acid-Schiff-positive and diastase-resistant. Immunohistochemically, the tumor cells were positive to anti-vimentin and anti-desmin antibodies and a few cells showed positivity to anti-actin antibody as well. They did not react to myoglobin, S-100 protein, and glial fibrillary acidic protein (GFAP). Electron microscopic studies revealed that the tumor cells had pinocytotic vesicles, dense plaque and microfilaments. The first granular cell variant of myogenic tumor reported here in Djungarian hamsters was differentiated from granular cell tumor of Schwann cell origin.     

The effects of a single injection of dexamethasone-21-isonicotinate on the lymphocyte functions of dairy cows at two weeks post partum

Dexamethasone is a potent therapeutic for treatment of the fatty liver syndrome or primary ketosis in post partum dairy cows. Reservations exist, however, among practitioners with respect to the risk of immunosuppression induced by corticosteroids. The aim of this study was to investigate the effect of a single injection of dexamethasone-21-isonicotinate on distinct immune functions of postpartum dairy cows because only scarce information is available on the effects of corticosteroid preparations when administered at a dosage and frequency for treatment of the fatty liver syndrome or primary ketosis. Sixteen Swedish red-pied dairy cows, between days 9 and 15 post partum, were allotted to either a control group (n = 8) or a treatment group (n = 8). The cows in the treatment group received a single intramuscular injection of a dexamethasone-21-isonicotinate suspension at a dosage of 0.02 mg/kg i.m. at the start of the experiment. White blood cell counts and selected lymphocyte functions (lymphocyte proliferation, expression of lymphocyte markers and the b2 and a4 chain of adhesion molecules belonging to the integrin family) and some parameters of the energy metabolism (glucose, insulin) were determined before the administration of corticosteroids (day 0) and subsequently at days 2, 4, 7 and 9 of the experiment. Changes in glucose and insulin were within the target range for treatment of the fatty liver syndrome or primary ketosis. Significant (P < 0.05) increases in the number of circulating white blood cells were observed in treated cows on the second day following treatment which was exclusively caused by an increase in the number of circulating neutrophils. Lymphocyte blastogenesis in response to ConA and the percentages of lymphocytes positive for CD2, CD4, CD8, CD49d and CD18 as well as the intensity of CD49d expression did not differ between the treatment and control groups. There was, however, a significant reduction (P < 0.01) in the intensity of CD18 expression on lymphocytes in the treated animals on the fourth day after treatment. In conclusion, a single administration of dexamethasone-21-isonicotinate in a dosage of 0.02 mg/kg i.m. at two weeks post partum in healthy cows had a significant but highly transient effect on CD18 expression on lymphocytes and the number of peripheral blood neutrophils, but did not affect lymphocyte blastogenesis or lymphocyte subpopulation patterns in peripheral blood.     

Effect of field pea level on intake, digestion, microbial efficiency, ruminal fermentation, and in situ disappearance in beef steers fed growing diets

Effects of increasing level of field pea (variety: Profi) on intake, digestion, microbial efficiency, and ruminal fermentation were evaluated in beef steers fed growing diets. Four ruminally and duodenally cannulated crossbred beef steers (367+/-48 kg initial BW) were used in a 4 x 4 Latin square. The control diet consisted of 50% corn, 23% corn silage, 23% alfalfa hay, and 4% supplement (DM basis). Treatments were field pea replacing corn at 0, 33, 67, or 100%. Diets were formulated to contain a minimum of 12% CP, 0.62% Ca, 0.3% P, and 0.8% K (DM basis). Each period was 14 d long. Steers were adapted to the diets for 9 d. On d 10 to 14, intakes were measured. Field pea was incubated in situ, beginning on d 10, for 0, 2, 4, 8, 12, 16, 24, 36, 48, 72, and 96 h. Bags were inserted in reverse order, and all bags were removed at 0 h. Ruminal fluid was collected and pH recorded at -2, 0, 2, 4, 6, 8, 10, and 12 h after feeding on d 13. Duodenal samples were taken for three consecutive days beginning on d 10 in a manner that allowed for a collection to take place every other hour over a 24-h period. Linear, quadratic, and cubic contrasts were used to compare treatments. There were no differences in DMI (12.46 kg/d, 3.16% BW; P > 0.46). Ruminal dry matter fill (P = 0.02) and mean ruminal pH (P = 0.009) decreased linearly with increasing field pea level. Ruminal ammonia-N (P < 0.001) and total VFA concentrations (P = 0.01) increased linearly with increasing field pea level. Total-tract disappearance of OM (P = 0.03), N (P = 0.01), NDF (P = 0.02), and ADF (P = 0.05) increased linearly with an increasing field pea level. There were no differences in total-tract disappearance of starch (P = 0.35). True ruminal N disappearance increased linearly (P < 0.001) with increasing field pea level. There were no differences in ruminal disappearance of OM (P = 0.79), starch (P = 0.77), NDF (P = 0.21), or ADF (P = 0.77). Treatment did not affect microbial efficiency (P = 0.27). Field pea is a highly digestible, nutrient-dense legume grain that ferments rapidly in the rumen. Because of their relatively high level of protein, including field peas in growing diets will decrease the need for protein supplementation. Based on these data, it seems that field pea is a suitable substitute for corn in growing diets.